A large part of the story revolves around hauling a locomotive and tender by mule teams across many miles of land without the benefit of railroad tracks. This would be impossible for two reasons. 1. The loco and tender are heavy, the loco weighing at least 10 tons and the loaded tender weighing more than 5 tons, and the steel wheels would sink into the ground instead of rolling and 2. There is no way to steer the front wheels of the loco or the wheels of the tender.